P-chloroazo compounds



United States Patent Int. C1. C09]: 43/00; C07c 107/04 US. Cl. 260-205 2 Claims ABSTRACT OF THE DISCLOSURE Production of a p-chloroazo compound by reacting an aromatic azo compound bearing a hydroxy group in pposition to the azo group with phosgenc in an inert organic solvent and in the presence of an N,N-disubstituted carboxylic amide. The resulting compounds are useful as pesticides or as a source of typical azo dyes.

This invention relates to a process for the production of organic compounds containing chlorine. It relates particularly to the production of azo compounds which bear in one of the two para-positions to the azo grouping a chlorine atom, with or without further susbtituents in other positions.

We have found that pchloroazo compounds are obtained when an aromatic compound which bears a hydroxyl group in p-position to an azo group is reacted with phosgene in an inert organic solvent in thepresence of an N,N-disubstituted carboxylic amide.

It is an advantage of the invention that it makes available a large number of compounds (some of them new) from which, for example, very valuable substances may be prepared, in particular fast dyes and other valuable substances, as for example biocides. By the new process it is possible to carry out a chlorination with elimination of a hydroxyl group previously present (which has not hitherto been possible) in a particularly simple way which is surprising as compared with prior art methods.

Azo compounds containing hydroxyl groups which are used as initial materials for the new process may be obtained by known reactions, for example by coupling diazo compounds to aromatic hydroxyl compounds having an unsubstituted p-position. Examples of suitable compounds are: the coupling products of aniline, the toluidines, chloroanilines, nitroanilines, nitrochloroanilines, nitrotoluidines, nitroaminoanisols, N,N dialkylsulfanilamides and the halogenation products of these compounds and those of benzidine, 1-amino-4-chloro-naphthalene and the like with aromatic hydroxyl compounds which do not contain a su bstituent in p-position, such as phenol, o-cresol, m-cresol, o-chlorophenol, m-chlorophenol, o-nitrophenol, m-nitrophenol, 2-'chloro-6nitrophenol, esters of salicylic acid, a-naphthol and so on. Other monoazo or disazo phenols or naphthols which contain "Ice wherein R is a member selected from the group consisting of a chlorine atom and nitro, carboxylic ester phenyl azo andsulfonamido groups, R and'R are members selected from the group consisting of hydrogen atoms, halogen atoms and nitro, alkoxy, lower alkyl and carboxylic ester groups, R, is a member seletced from the group consisting of a hydrogen atom, a chlorine atom and alkoxy, lower alkyl and carboxylic ester groups and R is a member selected from the group consisting of a hydrogen atom and nitro and carboxylic ester groups. Among the compounds having the above general formula, those compounds which have the following general formula are new:

where R is a member selected from the group consisting of a chlorine atom, and nitro, carboxylic ester, phenyl azo and sulfonamido groups, R and R are members selected from the group consisting of hydrogen atoms, chlorine and bromine atoms and nitro, alkoxy, lower alkyl and carboxylic ester groups, R, is a member selected from the group consisting of a hydrogen atom, chlorine atom and alkoxy, lower alkyl and carboxylic ester groups and R is a member selected from the group consisting of nitro and carboxylic ester groups.

Among the N,N-dialkyl substituted carboxylic amides those are particularly suitable which contain lower alkyl radicals having up to about four carbon atoms and which substitucnts of any type which are inert under the reacare derived from carboxylic acids having up to six carbon atoms. Preferred compounds are N,N-dimethyl formamide and tearamethyl urea.

Examples of dialkyl carboxylic amides which are suitable for the new process are diethyl formamide, dipropyl formamide, dimethyl acetamide, dibutyl caproamide, dimethyl stearamide, tetramethyl adipic diamide, N-alkyl lactams having five to thirteen ring members and one to four carbon atoms in the alkyl radical, tetraalkyl ureas having one to four carbon atoms in the alkyl radical, N-formylated cyclic imines having five to seven ring members, such as N-formylpyrrolidine, N-formylmorpholine and N,N'-bis-formylpiper azine. I v

The amount of phosgefne used for chlorination in the new process may vary within wide limits; in general at least 1 mole (with reference to the initial material used) is used provided the initial material contains only one hydroxyl group. If more than one hydroxyl group: is pres-.

ent, correspondingly larger amounts of phosgene are naturally required for complete reaction of the hydroxyl The temperatures chosenare usually from 40 to 200' C., particularly from to C., but higher reaction temperatures may also be used.

All organic liquids which are inert under the reaction conditions are suitable as organic solvents or diluents, for example toluene, chlorobenzene, dichlorobenzene, nitrobenzene, decahydronaphthalene and the like. They may be used in the ratio of 1:1 to l: 10 and the more concentrated reaction media (for example dilution ratios of from about 1:2 to about 1:4) are advantageous. It is possible, but not necessary, to use superatmospheric pressure.

The products are in general worked up by conventional methods for example by suction filtration and if desired subsequent washing, for example with methanol or ben- I zene.

It is peculiar that when using known chlorinating agents, as for example phosphorus pentachloride, sulfuryl chloride of benzenesulfonyl chloride, the p-position of the initial materials for the new process cannot be substituted. It is therefore surprising that phosgene, whieh reacts by elimination of hydrogen eholride, should give a smooth reaction with these basic azo compounds with substitution of the hydroxyl groups if N,N-disubstituted carboxylic amides be used as catalysts.

The compounds obtainable by the new process (some of which are new) may be used as 'biocides, for example as pesticides, and also as intermediates for the production Initialmaterlal O N I N0 1 of dyes. not

The invention is illustrated by the following examples. The parts specified in the examples are parts by Weight. 6' N= N or EXAMPLEI I I b 288 parts of 3,4-dinitro-4-hydroxy-azobenzene is sus- I 7 I pended in 900 parts of dichlorobenzene. 10 parts of dii I methylformamide is add-ed and a powerful current of n phosgene is passed through the mixture which is heated to 115 C. Four hours later it is allowed to cool and the .I p llroz I p I ;product is suction filtered, washed with methanol and U y I dried. 220 parts of the compound having the formula: f I v N02 1702 I 12 02s +N= N- 01i I i 11102 o1 o1 is obtained. v

Analytical values.-Calcnlated: Chlorine, 11.4%; nitrogen, 18.3%. Found: Chlorine, 11.8%; nitrogen 17.5%.

EXAMPLE 2 14- The procedure of Example 1 is followed but 3,4-cli- I I nitro-4-hydroxyazobenzene is replaced by the azophenols 40 or azonaphthols shown in the following table, together 15 with the solvents in the ratios and at the temperatures given in the table. The amounts of p-chloroazo compounds given in the table are obtained.

Initial material 3o r I I 1i 02N I N =N 0n 2 N-SOPQ-NQPQ-OH I v r Br" N02 v H30 i Y II C v 3O2N N:N H II I -1-- I y p r f v. 11. 2. N02 (n-s0"- N- N on i H l 1. "1 I I? I i I. N02 I {$2N v Erin '1- J2 I. i 9 I I I .I I, N02 I NO? Initialmaterial. .1- w ..v Initialmaterial t OCH; c1 7 CH3 CH3 22 O2NN=N .36 02NN=N/ 0H I I 0 N02 l I COO-GHrCHg N02 CH OCH Bl CH3 0 N- N=N OH 43 2 Q Q n N 02 N02 The columns in the following table have the following significance: r Y "IMF-which of the above initial materials is used and the "If amount used is given in brackets l Solvent=the solvent used and the amount used in brackets DM=the amount of dirnethylformamide used T C.=the reaction temperature in C.

Yield (p, percent) =the yield in parts and percentage.

Yield Solvent DM T., 0. Parts Percent Toluene (350) 5 110 86 73 o-Dlchlorobenzene (250)... 2 120 41 78 o-Dichlorobenzene (500)... 5 120 72 68 4( 0) o-Diehlorobenzene (700)... 12 120 282 77 5(150) o-Diehlorobenzene (400)-.. 6 120 67 43 6027) Toluene 6 105 55 40 7(210) o-Dichlorobenzene (420) 8 90 180 80 8(230) o-Dichlorobenzene (460) 12 120 142 58 9(155) Toluene (280) 10 105 73 45 10(200 Chlorobenzene (300 20 105 131 62 11(50) o-Diehlorobenzene (1 3 120 25 48 12(111) o-Dichlorobenzene (200)". 10 120 73 69 13(100) Benzene (200) 5 65 62 14(50) o-Dichlorobenz ene (125) 2 120 20 38 15(35) o-Dichlorob'enzene 2 22 60 16(125)'... o-Diehlorobenzene (250)-" 10 84 64 17(103).- Toluene (200) 10 105 40 37 70 18(120) Toluene (360) 10 105 92 73 o-Diehlorobenzene (340) 13 120 77 32 oD1ehlorobenzene (300) 10 102 97 o-Dlohlorobenzene (220).-- 10 120 82 65 0Diehlorobenzene (300) 12 120 71 45 o-Dichlorobenzene 5 120 30 47 o-Diehlorobenzene 8 120 41 50 N0; 0-Dich1orobenzene (250) 10 120 48 46 Yield Yield 1M Solvent DM '1., 0. Parts Percent IM S Catalyst (parts) '1., 0. Parts Percent 26(150) o-Dichlorobenzepe (150 15 130-140 114 70 1(100)- 250 N-methylpyrrolidone (10) 120 25 23 27(160) o-Dichlorobenzene (190)"- 16 120 95 57 2(65) 160 Tetramethylurea (6) r 120 42 61 28(10 o-Dichlorobenzene (200)--. 10 120 23 44 3000)"- 250 Dipropylformsm ide 120 58 54 2 o-Dichlorohenzene (220)"- 11 120 86 75 4(100). 250 Dimethylaeetamide (10) 120 34 32 o-Dichlorohenzene (300). 15 120 96 59 5(87) 90 Tetramethylurea (9)... 130 24 26 81(120) 0-Dit1hlorobenzene (240)-.. 6 120 85 68 32(141).- o-Dichlorobenzene (280) 14 120 119 85 o-gi g omgemne 1:3 We Claim: 5 0- ic oro enzeue 0 35(151) o-Dielllorobenzene 225 15 120 10s as 10 An compound havmg the formula o-Diehlorobenzeno (230)... 16 120 108 65 R4 R4 o-Dichlorobenzene (270)... 13 100 130 91 o-Dic'hlorobenzene (520)-.. 26 120 216 78 Toluene (675) 27 100-110 180 64 o-Dichlorobenzene (480)--. 24 120 181 71 o-Dichlorobenzene (550)....- 27 120 141 49 I 42(160). o-Dichlorobenzene (320)--- 16 120 86 51 R3 R5 43(200 o-Dichlorobenzene (400)... 120 139 (26 9 I H l--- 11 120 90 wherein R is a member selected from the group consisting of chlorine, nitro, methyl carboxylic ester, ethyl car- EXAMPLE 3 The procedure of Example 2 is followed but using the catalysts, initial materials and reaction conditions shown in the following table:

Initial material In the following table, S gives the amount (in parts) of o-dichlorobenzene used as solvent.

boxylic ester, phenyl azo, and dimethyl sulfonamido, R is a member selected from the group consisting of hydrogen, bromine, chlorine, nitro, methyl, methoxy, methyl carboxylic ester and ethyl carboxylic ester, R is a member selected from the group consisting of hydrogen, bromine, chlorine, nitro, methyl and methoxy, R is a member selected from the group consisting of hydrogen, chlorine, methyl, methoxy, methyl carboxylic ester and ethyl carboxylic ester and R is a member selected from the group consisting of nitro and the methyl-, ethyl-, methoxyethyland chloroethylcarboxylic ester groups, with th proviso that a carboxylic ester group appears not more than once on a phenyl nucleus.

2. The compound of the formula US. Cl. X.R.

@33 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent 3.498.968 DatedMaroh 3, 1970 Inv Peter Dimroth et a1 It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

[- Column 1, line 51, "pounds" should read --pounds,--.

Column 2, line 35, "tearamethyl" should read --tetramethy1--.

Column 6, formula 39, that portion of the formula reading "B" should read --Br--.

golumn 8, claim 1, that portion of the formula reading 124 II Re R;@ should read R;

SIGNED AND SEALED JUL 2 8 1970 uS .Attcat:

Edwlrdml 'lohhqlt. MIAM r. T Attesting Officer ms 

